In general, a steering wheel assembly for vehicles includes a steering wheel, a steering column, a steering roll connector assembly, and a multi-functional switch assembly. The steering wheel is intended to allow a driver to set a steering direction. The rotation of the steering wheel by the driver is transferred to the wheels of a vehicle through the steering column to set the steering angle of the vehicle wheel. The multi-functional switch assembly includes a light and a fog lamp, a wiper, various audio devices, and a vehicle window switch, and the like. The multi-functional switch assembly serves to prevent the driver's driving attention from being dissipated even during manipulation of a wide variety of devices by increasing the manipulability of the various devices. The multi-functional switch assembly is implemented as a button switch mounted on a top of the steering wheel, or a lever switch mounted on a side of the steering wheel. In addition, the steering wheel includes an air bag mounted on the top thereof to ensure the safety of the driver.
A roll connector is necessarily included which is constructed to establish the electrical communication with a wide range of electrical and electronic equipment included in a steering wheel assembly and supply electric power. Japanese Patent Laid-Open Publication No. Hei 4-87191 discloses a roll connector according to the prior art, which includes an outer pipe having a central hole formed at the center thereof, and a flexible cable fixed at one side thereof to the outer pipe and fixed at the other side thereof to an inner pipe, the flexible cable being accommodated between the outer pipe and the inner pipe in such a manner as to be wound in a clockwise direction on the inner wall of the outer pipe to be inverted in a U-shape and wound in a counterclockwise direction around the outer wall of the inner pipe.
Such a roll connector necessarily requires that its neutral position should be secured in the assembly process of the steering wheel assembly. That is, the roll connector must be delivered to an automotive assembly line in a state in which the relative rotation between a stator and a rotor included in the roll connector is prevented so as to able to accurately detect the amount of rotation of the steering wheel. A roll connector mounted with a neutral pin to secure the neutral position of the roll connector is supplied and logistically transported to an automotive assembly company. This roll connector according to the prior art is joined to a steering wheel shaft and is connected to a switch connector for transferring electric signals of switches of the steering wheel in an automotive assembly process. The conventional neutral pin causes an interference with an assembly position of the switch connector, which makes it impossible to pre-fabricate the switch connector.
The separate delivery of such respective elements to the automobile assembler involves a considerable problem in that logistics costs are increased, and there is a high possibility of erroneous assembly due to the presence of a complicated wire harness during the assembly of a car. In addition, the convention roll connector entails a problem in that it includes only a neutral pin with a detachable structure, so that when the car is re-assembled due to a problem of erroneous assembly occurring after removal of the neutral pin, the neutral position of the roll connector is released, thereby greatly deteriorating workability.